Text Searching on a Heterogeneous Cluster of Workstations
计算机专业英语2013影印版课后答案（ComputingEssentials2013）选择题
计算机专业英语2013影印版课后答案（ComputingEssentials2013）选择题计算机专业英语2013影印版课后答案（Computing Essentials 2013）选择题Multiple 11. The keyboard, mouse, monitor, and system unit are:hardware output devices storage devices software2. Programs that coordinate computer resources, provide an interface, and run applications are known as:application programs operating systemsstorage systems utility programs3. A browser is an example of a:basic application specialized programsystem application utility program4. Although not as powerful as a supercomputer, this type of computer is capable of great processing speeds and data storage.mainframe media center midrange netbook5. The smallest type of microcomputer:netbook handheld midrange tablet PC6. RAM is a type of:computer memory network secondary storage 7. Unlike memory, this type of storage holds data and programs even after electrical power to the computer system has been turned off.primary RAM ROM secondary8. The type of file created by word processors to save, for example, memos, term papers, and letters.database document presentation worksheet9. The change in connectivity that uses the Internet and the Web to shift many computer activities from a user’s comput er to computers on the Internet.cloud computing high definition network USB10. The largest network in the world is [the]:Facbeook Internet Web USBMultiple 21. The network that connects computers all over the world.CERN Internet LAN Web2. The rules for exchanging data between computers.DSL protocols Web WWW3. Client-based e-mail accounts require this special program to be installed on your computer.e-mail client hyperlink Java utility4. Communities of individuals who share a common interest typically create Facebook:clients groups pages profiles5. E-mail that does not require an e-mail program installed on a user's computer is known as:blog podcast Webmail utility6. A very well-known microblog.LinkedIn MySpace Twitter Wikipedia7. These programs continually look for new information and update search services’ database programs.filters IM spiders wikis8. A type of search engine that submits requests to other search engines, organizes their responses, eliminates duplicate responses, orders hits, and then provides an edited list.directory search ISPmetasearch engine specialized search engine9. This is th e Internet’s equivalent to traditional cash.digital cash e-commerce icash Internet dollars 10. Using file transfer utility software, you can copy files to your computer from specially configured servers on the Internet. This is called:downloading filtering blogging uploadingMultiple 31. This type of software works with end users, application software, and computer hardware to handle the majority of technical details.application general purpose system utility2. A rectangular area that can contain a document, program, or message.dialog box form frame window3. Programs that create text-based documents.DBMS suites spreadsheets word processors 4. Programs that organize, analyze, and graph numeric data such as budgets and financial reports.DBMS suites spreadsheets word processors5. In a spreadsheet, the intersection of a row and column creates a:cell formula function label6. A collection of related data that is the electronic equivalent of a file cabinet.cell database document table7. A database tool that will quickly rearrange a table’s records according to a selected field.filter sort spreadsheet word processor8. Programs that combine a variety of visual objects to create attractive, visually interesting presentations.DBMS presentation graphics spreadsheet word processor 9. The primary disadvantage of this type of package is that the capabilities of each function are not as extensive as in individual programs.integrated office software utility10. A type of suite stored at a server on the Internet and available anywhere through Internet access.cloud integrated office utilityMultiple 41. These specialized graphics programs combine text and graphics to create publications of professional quality.desktop publishing programs image editorsimage galleries illustration programs2. Also known as drawing programs.desktop publishing programs image editorsimage galleries illustration programs3. Graphics programs used to create and edit vector images.desktop publishing programs image editorsimage galleries illustration programs4. An essential multimedia feature that allows user participation.Flash interactivity immersion raster5. Special programs used to create multimedia presentations.desktop publishing programs Flash editorsimage editors multimedia authoring programs 6. A widely used interactive animation application from Adobe.ACTION Flash Fuzzy WYSIWYG7. Programs for Web site design and HTML coding are called Web page editors orapps HTML editors VR programs Web editors8. This area of artificial intelligence is also known as expert systems.acoustics knowledge-based systems robotics virtual reality 9. A type of artificial intelligence that uses a database to provide assistance to users.acoustics expert systems robotics virtual reality 10. Another name for the database used in expert systems that contains specific facts and rules.access table expert table knowledge base rule baseMultiple 51. What type of software works with users, application software, and computer hardware to handle the majority of technical details?dapplication desktop Linux system2. The programs that convert programming instructions written by programmers into a language that computers understand and process are language: converters linguists managers translators3. The ability to switch between different applications stored in memory is called:diversion multitasking operational interference programming 4. Graphic representations for a program, type of file, or function: app icon image software5. This operating system feature is controlled by a mouse and changes shape depending on its current function.dialog box menu mouse pointer6. The operating system based on Linux, designed for Netbook computers, and focused on Internet connectivity throughcloud computing:Chrome Mac Unix Windows7. The mobile operating system developed by Apple and originally called iPhone OS:Android BlackBerry OS IOS Mac OS8. A utility program that makes copies of files to be used in case the originals are lost or damaged:Backup and Restore Disk Cleanup Disk Defragmenter Compactor 9. A troubleshooting utility that identifies and eliminates nonessential files, frees up valuable disk space, and improves system performance:Backup and Restore Disk Cleanup Disk Defragmenter Compactor 10. Windows makes it easy to update drivers with Windows:Backup Restore Driver UpdateMultiple 61. This container houses most of the electrical components for a computer system.carrier package system board system unit TV tuner2. Similar to notebooks, this system unit specializes in on-the-go Web browsing and e-mail access.chassis desktop media center netbook3. Computers can only recognize this type of electronic signal.analog bus digital maximum4. The main or motherboard is also known as the:computer board processor mobile system system board 5. How many bytes can a 32-bit-word computer access at one time?1 48 166. In a microcomputer system, the central processing unit is contained on a single:bus chip module RAM7. This type of memory divides large programs into parts and stores the parts ona secondary storage device.direct expanded random-access virtual8. Also known as NIC, this adapter card is used to connect a computer to a:AIA expansion graphics network9. This provides a pathway to connect parts of the CPU to each other.bus Plug and Play wired wireless10. Older ports that have largely been replaced by faster, more flexible ports are called:buses expandable legacy renderedMultiple 71. Most keyboards use an arrangement of keys known as:Alpha Daisy OptiKey QWERTY2. The device that controls a pointer displayed on the monitor.cord mouse printer scanner3. Also known as a roller ball, this device controls the pointer by rotating a ball with your thumb.trackball joystick cordless mouse stylus4. The type of screen that can be touched with more than one finger and supports zooming in and out by pinching and stretching your fingers.digital dynamic multitouch OLED5. Flatbed and document are types of:headsets HDTVs monitors scanners6. Device used by banks to automatically read those unusual numbers on the bottom of checks and deposit slips.MICR FDIC OMR UPC7. The most widely used audio-input device.mouse VR microphone TFT8. The monitor feature that specifies how often a displayed image is updated.aspect ratio dot pitch refresh rate resolution rate 9. Handheld, book-sized devices that display text and graphics.e-book readers HDTV lasers whiteboards10. This technology allows television stations to broadcast their programming directly to smartphones, computers, and digital media players.CRT HDTV LED Mobile DTVMultiple 81. RAM is sometimes referred to as:primary storage ratio active memoryread only memory secondary storage2. The actual physical material that holds the data and programs.primary storage media disk access3. Measures how tightly these charges can be packed next to one another on the disk.density cylinders tracks sectors4. When a read/write head makes contact with the hard disk’s surface, it causesa head:crash land pit scratch5. This hard-disk performance enhancement anticipates data needs.disk caching file compression file decompression RAID6. This type of storage uses pits and lands to represent 1s and 0s.cloud hard disk optical solid state7. DVD stands for:digital versatile disc digital video datadynamic versatile disc dynamic video disc8. USB drives are also known as:flash drives optical drives ports universal state bus9. An organizational strategy to promote efficient and safe use of data across the networks.cloud dynamic data mission statemententerprise storage system RAID10. A mass storage device that provides access to data archived on tapes.file system NAS RAID system tape libraryMultiple 91. The concept related to using computer networks to link people and resources.connectivity GPS TCP/IP Wi-Fi2. A high-frequency transmission cable that delivers television signals as well as connects computers in a network. coaxial hi def 3-D twisted pair3. A short-range radio communication standard that transmits data over short distances of up to approximately 30 feet. Bluetooth broadband DSL TCP/IP4. The speed with which a modem transmits data is called its:digital velocity dynamic rate modular rating transfer rate5. The bandwidth typically used for DSL, cable, and satellite connections to the Internet.baseband broadband medium band voiceband6. Every computer on the Internet has a unique numeric address called a(n):IP address DNS broadcast packet7. Sometimes referred to as a LAN adapter, these expansion cards connect a computer to a network.PCMCIA NIC server VPN8. A device that allows one LAN to be linked to other LANs or to larger networks.IDS network gateway PAN switch9. Typically using Wi-Fi technology, these wireless access points are typically available from public places such as coffee shops, libraries, bookstores, colleges, and universities.hotspots extranets PANs LANs10. Star, tree, and mesh are three types of network:topologies protocols strategies devicesMultiple 101. The three primary privacy issues are accuracy, property, and:access ethics ownership security2. To easily get names, addresses, and other details about a person using only his or her telephone number, government authorities and others use a(n): adware cookie keystroke logger reverse directory worm3. Browsers store the locations of sites visited in a:history menu tool bar firewall4. The browser mode that eliminates history files and blocks most cookies.detect insert privacy sleep5. The information that people voluntarily post in social networking sites, blogs, and photo- and video-sharing sites is used to create their:access approval firewall online identity phish6. Computer criminals who specialize in stealing, trading, and using stolen credit cards over the Internet are known as: carders card scammers cyber traders identity thieves7. Programs that come into a computer system disguised as something else are called:Trojan horses viruses Web bugs zombies8. The use of the Internet, cell phones, or other devices to send or post content intended to hurt or embarrass another person is known as:cyber-bullying online harassmentsocial media discrimination unethical communication9. Special hardware and software used to con trol access to a corporation’s private network is known as a(n):antivirus program communication gatefirewall spyware removal program10. To prevent copyright violations, corporations often use:ACT DRM VPN WPAMultiple 111. People who react to technology by thinking computers are magic boxes capable of solving all kinds of problems that computers really can’t handle are: cynics frustrated na?ve proactive2. The type of person that looks at technology in a positive realistic way is:cynical proactive na?ve frustrated3. Books, journals, and trade associations are the best sources to help you:develop personal contacts develop specialtieslook for innovative opportunities maintain your computer competency 4. If your career is in marketing, it makes sense to develop a specialty in:database desktop publishingprogramming systems analysis and design5. What computer professional repairs and installs computer components and systems?computer technician data entry workerdesktop publisher software engineer6. What computer professional designs, tests, and researches encryption procedures?cryptographer network administratorprogrammer software engineer7. What computer professional uses database management software to determine the most efficient ways to organize and access data?cryptographer database administratorprogrammer software engineer8. What computer professional oversees the work of programmers, computer specialists, systems analysts, and other computer professionals?information systems manager network managersoftware engineer technical writer9. What computer professional creates, tests, and troubleshoots computer programs?network manager programmersoftware engineer technical writer10. What computer professional plans and designs information systems?network manager programmersoftware engineer systems analyst。
生态景观20篇英文文献
A user-friendly PC-based GIS for forest entomology: anattempt to combine existing softwareMARIUS GILBERTLaboratoire de Biologie animale et cellulaire, CP 160/12Université Libre de Bruxelles, 50 av. F. D. Roosevelt, 1050 Brussels, BelgiumA BSTRACT We present a combination of existing software which should facilitate the use of GIS by forest entomologists. The use of existing GIS by ecologists who want to take advantage of the spatial component of their analyses is often hindered by the difficulty of use and cost of such tools. Moreover, it might be useful to have a system which can be carried to remote locations where access to a mainframe computer or powerful workstations is unavailable. It is now possible to have a good system running on a single personal computer due to the increasing power and the low cost of this type of hardware. We have gathered programs characterised by their simplicity, low cost, and performances. IDRISI is a simple and inexpensive GIS which has a simple file structure that allows the user to create his/her own analysis scripts with basic knowledge in computer science. VARIOWIN is a geostatistical package which performs exploratory variography and 2D modelling. SURFER is a surface mapping system able to create and to display grids using several methods of spatial interpolations including two dimensional anisotropic kriging. FRAGSTATS is a program which performs landscape analyses and finally, COREL DRAW is a vector-oriented package that can be used for output of both bitmap and vector output. These programs were not designed to work together and problems may occur due to the heterogeneous nature of the system. Conversion file difficulties were encountered and we were faced with the complexity of using different programs to perform one analysis sequence. An additional module is being developed to solve these problems and the whole system should be able to manage data, analyze their spatial component and display map output in a simple and user-friendly way.K EY W ORDS: GIS, Spatial analysis, geostatistics, software.G EOGRAPHICAL INFORMATION SYSTEMS (GIS) are widely used in environmental management (Burrough 1993). In ecology and particularly in forest entomology they may be of considerable interest for the study of spatial pattern and insect spatial distribution (Liebhold et al. 1993, Coulson et al. 1993, Turner 1989). For example, the measurement of spatial dependence is essential in sampling methodology (Rossi et al. 1992, Legendre 1993, Fortin et al. 1989). Moreover, the interaction between insects and their environment always bears a spatial component (Borth and Hubert 1987, Hohn et al. 1993).A GIS is a computer program designed to collect, retrieve, transform, display, and analyze spatial data. GIS can incorporate georeferenced data to produce maps or layers. Usually, a map layer or a theme is composed of only one type of data. GIS have the ability to import and manage data from different sources: mapped data, alphanumeric data, remotely sensed data. These types of data may then be combined to build a GIS database. Using this database, the user may create map outputs or display views relative to specific questions. These systems have recently improved their abilities to carry out spatial analyses integrating new built-in functions (spatial interpolation, spatial autocorrelation, overlay analysis, etc.). Furthermore, the user may create his own analysis functions with personal scripts.Pages 54-61 in J.C. Grégoire, A.M. Liebhold, F.M. Stephen, K.R. Day, and S.M. Salom, editors. 1997. Proceedings: Integrating cultural tactics into the management of bark beetle and reforestation pests. USDA Forest Service General Technical Report NE-236.G ILBERT55New GIS users often must choose between the performances of their system and the time that they will spend to be able to use it. Simple systems are easy to learn, but often lack integrated functions which obliges the user to write his/her own script to achieve specific goals.Powerful systems are created for a diversity of purposes. They bear useful built-in functions, but users must become familiar with the whole GIS environment to use them properly. These powerful systems usually run on workstations. This type of hardware and associated software are expensive and demand knowledge of a new operating system environment. For example, the use of an important application software such ARC/INFO demands knowledge in the UNIX operating system, knowledge of the ARC/INFO file structure and topology, of the ARC/INFO high number of commands and of the AML (Arc Macro Language).However, users who just want to take advantage of the spatial component of their data have different hardware and software requirements than users who are planning complete GIS research projects involving extensive data census. The first kind of users can not afford expensive systems to add a spatial analysis component to their ecological studies. This is why an inexpensive system working on a single PC might interest such users. Moreover, the increasing power of PCs makes GIS more and more efficient on this hardware. Finally, a system running on a single PC might be useful on the field or to remote locations where access to mainframe computer or powerful workstations is unavailable (Carver et al. 1995).We present a combination of inexpensive and user-friendly PC-based software which should help potential users to integrate spatial components to their ecological studies.System PresentationFirst, information about existing software was collected, mostly on the Internet in Web pages. Additionally, user discussions available in newsgroups related to each software were followed.The software applications were tested on a Pentium 90 MHz PC with 8 Mbytes of RAM, under the WINDOWS 95 operating system. ARC/INFO PC, MAPINFO and IDRISI have been tested for GIS functionality. VARIOWIN, Geostatistical Toolbox, Geo-EAS, FRAGSTATS and SURFER were tested as additional spatial analysis tools. These applications were first tested with external sample data and secondly with our own data. GIS were tested for their ability to create a new database, to manage it and especially to exchange data with other sources. Spatial analysis software were tested with the author's instructions.The chosen combination of software is presented in figure 1. IDRISI for WINDOWS (Clark University, Eastman 1988, Cartwright 1991) is a raster GIS which includes vector-data management and display. It is highly user-friendly and bears a lot of built-in spatial analysis functions. Its very simple file structure facilitate the creation of new analysis scripts. IDRISI for Windows includes a database manager which allows users to relate geographic features to a database (DBase, Access, text files). We used it in our system because of its simple file structure in both vector and raster formats and its ability to import and export data in a large range of formats (raster or vector geographical data or database data). This software is very inexpensive and will be used as the central geographical data manager of our system.G ILBERT56VARIOWIN- Exploratory variography- 2D modellingSURFER Surface mapping system EXCELTabular data managementADDITIONAL MODULE- Spatial analysis tools- Conversion tools- Help flow chartsCOREL DRAW Object oriented and bitmappedgraphic designIDRISIRaster and Vector GIS FRAGSTATSSpatial pattern analysis Figure 1: Structure of the system showing inputs and outputs between software.VARIOWIN, written by Yvan Pannatier (University of Lausanne - Switzerland,Pannatier 1994) has been released with a manual (Pannatier 1996). Its aim is to compute geostatistical analyses and variogram modelling in 2D. There are three modules. The first creates a pair-comparison file on the basis of an ASCII file containing XY co-ordinates and attributes. The second module computes variogram surfaces, directional variograms, and a general variogram. It is also possible to estimate the semi-variogram with other estimators like the non-ergotic covariance or the non-ergotic correlogram which are often used in ecology (Sokal and Oden 1978(a), 1978(b), Johnson 1989). Moreover, the user may also create H-scaterplots and identify interactively potential outliers affecting the measure of spatial continuity. The last module offers an excellent tool to interactively model the semi-variogram.SURFER (Golden Software, Inc.) is a surface mapping system designed to manage and display 3D raster-based data. Its first aim is to build surfaces by spatial interpolation on the basis of georeferenced data points. These interpolation methods include kriging but an input model created with another software has to be specified to perform it. The input and output files of VARIOWIN are fully compatible with the SURFER format and their combination has proved to be excellent to practice geostatistics. It is possible to export the interpolated grid in a format readable by IDRISI. The last version of SURFER has the capability to perform 2D anisotropic kriging with three nested structures.FRAGSTATS is a DOS-based spatial analysis program for quantifying landscape structure written by K. McGarigal and B. J. Marks (Oregon State University). Landscape ecology involves the study of the landscape pattern which can be associated with other ecological characteristics, including vertebrate and invertebrate populations (Saunders et al.1991, Turner 1989, Wiens et al. 1993). FRAGSTATS has been developed to quantify landscape structure by offering a comprehensive choice of landscape metrics. The PC version creates IDRISI raster-format files.COREL DRAW (Corel Corporation) is a well known object-oriented vector and bitmapped graphic design software which is able to import and export in most of the graphic file formats. It is very flexible and can be efficiently used to manipulate and print map output.EXCEL (Microsoft) is another well known software which is installed on many PCs.It may be used to manage input tabular data and output graphs and statistics.G ILBERT57Test With Our Own DataThis combination of software has been tested in two study cases. The aim of this test was to assess the system inadequacies in specific analyses and to list any problems encountered. These test studies concerned the spatial distribution of Pulvinaria regalis Canard in the city of Oxford (Speight et al. 1996) and Dendroctonus micans (Kug.) in the Massif central (unpublished). The use of the combined software in both cases is presented in Table 1. In both studies, IDRISI was used to manage the spatial data, VARIOWIN was used to calculate variograms, correlograms, correlogram surfaces, and for 2D isotropic and anisotropic modelling. SURFER was used to process kriging and to generate surfaces and map outputs. COREL DRAW was used to assemble the final map outputs. FRAGSTATS has not yet been tested with actual data.Table 1: Use of the software for different stages of the study cases.Software Pulvinaria regalis in the city of Oxford Dendroctonus micans in the Massif Central EXCEL Data encoding Data encodingExploratory Data Analysis Exploratory Data AnalysisGraph outputs Print output of the correlogramIDRISI Database construction Database constructionPlotting of the samples on a map Plotting of the samples on a mapQuadrat analysis Quadrat analysisMoving-Windows analysis Moving-Windows analysisSURFER Print output of the correlogram surface Isotropic 2D ordinary krigingAnisotropic 2D kriging Creation of a Digital elevation modelMap output of the density distribution Map output of the density distribution VARIOWIN Creation of a Pair Comparison File Creation of a Pair Comparison FileSemi-variogram and semi-variogram Semi-variogram and semi-variogram surfacessurfaces2D anisotropic semi-variogram modelling2D isotropic semi-variogram modelling COREL DRAW Digitizing streets contour lines Map output of the sample pointsMap output of the samples points Digitizing forest stands contour linesDigitizing altitude contour linesResults And DiscussionThe use of this combination of software is very easy to learn and use. The interactivity of the exploratory variography performed with VARIOWIN is an excellent method for becoming familiar with the basics of geostatistics and is highly recommended to beginners. The kriging function of SURFER is elementary and other software must be used to perform other types of kriging (Varekamp et. al. 1996). Moreover, the user must take care not to use the kriging function of SURFER as a black-box tool; users should be aware of the hypotheses and assumptions involved in a kriging process (Isaaks and Srivastava 1989). The surface-management and the map-output abilities of SURFER are highly complementary to a GIS such as IDRISI. FRAGSTATS has not been tested with our data but its use with data with the software provided is very easy. EXCEL and COREL DRAW are well known software58G ILBERTand we do not need to comment on them. Taken as a whole, the system met all the requirements of these two case studies and we plan to carry on with almost the same configuration for further studies. The proposed combination of software allowed us to perform file input, data management, spatial analyses and map outputs.However, considerable time was spent to solve computing problems. Basically, problems were caused by the fact that these applications were not designed to work together. First, some spatial analyses are not covered by this software combination. For example, a simple quadrat analysis might be used to determine whether sample spatial distribution is aggregative or not (Myers 1978). Second, the file formats used by the software are often different and conversion may involve a very detailed knowledge of the different software file structures. Fortunately, IDRISI allows the conversion of data from/to a wide range of formats. However we had problems even with the proper tools. For example, the missing data value used in the *.grd files used by VARIOWIN is not the same in the *.grd SURFER files (these files are described as having the same format). The grid files used by SURFER are binary files and must be first converted to ASCII files to be converted to IDRISI files. These problems are not serious if they can be easily identified, but they may otherwise cause important time losses. Sometimes, the automatic data transformations were not possible and we had to proceed manually within a text file. Third, due to the modular and heterogeneous structure of our system, we had to use different software to carry out an analysis sequence. For example, a basic geostatistical analysis involves exploratory data analysis (Tukey 1977) which can be computed with EXCEL, map output of the samples created with IDRISI, moving-windows analysis to detect sample-point aggregation and proportional effects calculated with separated programs (not included in the IDRISI analyses scripts), calculation of the estimated semi-variogram and its modeling carried out with VARIOWIN, and finally ordinary kriging processed with SURFER. This sequential analysis procedure was split into different small procedures within each software, with its own file input and output characteristics. Without an excellent knowledge of each software use and limitations, much time may be wasted.To meet these problems, we plan to write scripts in Visual Basic gathered in one new additional module. First, they compute spatial analyses which are not covered by the other software (e.g. quadrat and moving-windows analyses). Second, to simplify the file conversions, we will write flow charts indicating steps to convert files. These flow charts should underline sensitive steps (e.g. replacement of one no-data value by another). If a file-conversion tool does not exist in the software combination, we plan to write it. Finally, we plan to write flow charts for typical spatial analysis procedures. These flow charts will be designed to help users to know how and where they can perform a given analysis. This additional module (figure 1) should complement the system in a user-friendly way: the additional tools will complement the existing software, conversion procedures and the flow charts should reduce the wasted time needed to become familiar with all the individual programs.Varekamp et al. (1996) showed that it was possible to perform a wide range of geostatistical procedure with public-domain software available on the Internet (Englund and Sparks 1988, Pebesma 1993, Deutsch and Journel 1992). Their system is based on the use of DOS executable programs or FORTRAN routines which provide more geostatistical analysis functions than our system. We have chosen to focus on user-friendly and basic software. TheG ILBERT59 kriging abilities of SURFER are limited, but if a user wants to do more than two dimensional ordinary kriging, he can refer to other more powerful software (e.g. GSLIB) which is more complex and involves a better knowledge of spatial interpolation methods used in geostatistics. However, we insist on the fact that VARIOWIN is excellent for users to perform basic explorative and interactive variography and can be highly suggested for beginners users with geostatistics. Carver et. al. (1995) showed the advantages of having a GIS like IDRISI installed on a portable PC for expedition fieldwork (i.e. ability to develop sampling strategy as a result of immediate data visualisation). Additional spatial analysis modules enhance these advantages by a direct spatial analysis treatment of the data. For example, a strong spatial discontinuity in a species spatial distribution or a detection of data outliers might reveal interesting local environmental discontinuities. Such discontinuities detected afterwards are difficult to explain or interpret. Such fieldwork use of the GIS might then be of a considerable interest.Our system is basically designed for beginners in GIS and geostatistics, but we believe that even experienced users will find interest in a portable and inexpensive system which allows small budget projects. Moreover, experienced users may use the same combination of software as a base which can be supplemented with additional software whenever they reach limitations. The flexible structure of the system and the simple file structure used should facilitate the integration of additional modules.ConclusionTaken as a whole, this system could be used as a reliable, portable, and inexpensive PC-based GIS and spatial analysis tool. Problems due to the heterogeneous nature of the system have been encountered but they can be solved easily by a good knowledge of each software characteristics. An additional module should facilitate the use of this system by beginners. The flexible and simple structure of the system will facilitate the integration of additional modules by experienced users interested in different aspects of spatial analysis.AcknowledgementThe author would like to thank the Wiener-Anspach foundation for its funding support during all the stages of this work. This work was also funded by the FNRS (Fond National de la Recherche Scientifique) and the Loterie Nationale F 5/4/85 - OL - 9.708.References CitedBorth, P.W., and R.T. Huber.1987. Modelling pink bollworm establishment and dispersion in cotton with the Kriging technique, pp. 264. In Proceedings Beltwide Cotton Production Research Conference. Cotton Council Am. Memphis. 1987. Burrough, P.A.1986. Principle of Geographical Information Systems for land resources assessment. Clarendon Press, Oxford.Cartwright, J.C.1991. IDRISI - spatial analysis at a modest price. Gis-World, 4: 96-99.G ILBERT60Carver, S.J., S.C. Cornelius, D.I. Heywood, and D.A. Sear.1995. Using computer and Geographical Information Systems for expedition fieldwork. The Geographical Journal, 161: 167-176.Coulson R.N., J.W. Fitzgerald, M.C. Saunders, and F.L. Oliveira.1993. Spatial analysis and integrated pest management in a landscape ecological context, pp. 93. In Spatial Analysis and Forest Pest Management U.S. Dep. Agric., 1993.Deutsch, C.V., and A.G. Journel.1992. GSLIB Geostatistical Software Library and User's Guide. Oxford University Press, Oxford.Eastman, J.R.1988. IDRISI: a geographic analysis system for research applications.Operational-Geographer. 15: 17-21.Englund, E., and A. Sparks.1988. Geo-EAS 1.2.1 Users Guide. Report Number 60018-91/008, Environmental Protection Agency, EPA-EMSL, Las-Vegas, Nevada. Fortin, M.J., P. Drapeau, and P. Legendre.1989. Spatial autocorrelation and sampling design in plant ecology. Vegetatio, 83: 209-222.Hohn, M.E., A.M. Liebhold, and L.S. Gribko.1993. Geostatistical model for forecasting spatial dynamic of defoliation caused by the gypsy moth (Lepidoptera: Lymantriidae).Environ. Entomol. 23: 1066-1075.Isaaks, E.H., and R.M. Srivastava.1989. An Introduction to Applied Geostatistics.Oxford University Press, New-York.Jonhson, D.L.1989. Spatial autocorrelation, spatial modeling, and improvement in grasshopper survey methodology. Can. Entomol. 121: 579-588.Legendre, P.1993. Spatial autocorrelation: Trouble or new paradigm? Ecology (tempe), 74: 1659-1673.Liebhold, A.M., R.E. Rossi, and W.P. Kemp.1993. Geostatistics and geographic information systems in applied insect ecology. Ann. Rev. Entomol. 38: 303-327. Myers, J.H.1978. Selecting a measure of dispersion. Environ. Entomol. 7: 619-621. Pannatier, Y.1994. Statistics of Spatial Processes: Theory and Applications. pp. 165-170-In V. Capasso, G. Girone, and D. Posa (eds.), Bari.Pannatier Y.1996. VARIOWIN: Software for Spatial Data Analysis in 2D. Springer-Verlag, New York.Pebesma, E.J.1993. GSTAT 0.99h - Multivariate Geostatistical Toolbox. National Institute for Public Health and Environmental Protection, Bilthoven, The Netherlands. Rossi, R.E., D.J. Mulla, A.G. Journel, and E.H. Franz. 1992. Geostatistical tools for modeling and interpreting ecological spatial dependence. Ecological Monographs, 62: 277-314.Saunders, D., R.J. Hobbs, and C.R. Margules.1991. Biological consequences of ecosystem fragmentation: a review. Conserv. Biol. 5: 18-32.Sokal, R.R., and N.L. Oden.1978. Spatial autocorrelation in biology 1. Methodology.Biol. J. Linnean Soc. 10: 199-228.Sokal, R.R., and N.L. Oden. 1978. Spatial autocorrelation in biology 2. Some biological implication and four applications of evolutionary and ecological interest. Biol. J.Linnean Soc. 10: 229-249.Turner, M.G.1989. Landscape ecology: the effect of pattern on process. Annual Review of Ecology and Systematics, 20: 171-197.G ILBERT61 Varekamp, C., A.K. Skidmore, and P.A. Burrough. 1996. Using public domain geostatistical and GIS software for spatial interpolation. Photogrammetric Engineering & Remote Sensing, 62: 845-854.Wiens, J.A., N.C. Stenseth, and B. Van Horne.1993. Ecological mechanism and landscape ecology. OIKOS, 66: 369-380.。
高性能计算导论-introduction
OpenMP
OpenMP is a de-facto standard Application Programming Interface (API) to write shared memory parallel applications in C, C++, and Fortran. OpenMP is designed for shared memory machines. OpenMP is not designed to run across multiple machine like MPI.
Reduction of execution time Concurrency provided
HPC vs. Parallel
高性能计算与并行
硬件对高性能计算的支持
并行计算机模型
物理机器模型 抽象机器模型
主要用于设计、分析并行算法
物理（并行）机器模型
SIMD 计算机： Single-instruction multiple-data
Parallel computers offer the potential to concentrate computational resources
---processors---on important computational problems
Large scale of concentrated computational resources
PI计算问题求解
Through parallel computation
PI计算方法
简单的C程序计算PI
基于OpenMP的C程序计算PI
基于MPI的C程序计算PI
Reading
A cable from it was connected to the waterproof virtual display which presented the diver with a high contrast display“floating”in the field of view. A second cable was connected to the Kord Pad，a5-key device which the diver could hold in either hand and which was used to control the computer by pressing single or multiple keys. A Graphical User Interface（GUI）shows the user which key（or keys）to press. The GUI facilitates the wear ability and usability of the Wet PC—underwater computer. It was the result of several years of research into interface design and functionality. Rather like playing the piano，the user can interact with the computer in a very natural way—the diver can access and record information with one hand，even while swimming.
The Wet PC can help salvage-divers， maritime archeologists，and police divers find objects，record or look up information， or simply monitor their location at all times. Scientists could use the unit for mapping and monitoring coral reefs. Navy divers could use the Wet PC to search for mines and other unexploded devices.
计算机专业英语教程翻译完整版
1.1A Closer Look at the Processor and PrimaryStorage仔细看看处理器和主存储器We have learned that all computers have similar capabilities and perform essentially the same functions, although some might be faster than others. We have also learned that a computer system has input, output, storage, and processing components; that the processor is the “intelligence” of a computer system; and that a single computer system may have several processors. We have discussed how data are represented inside a computer system in electronic states called bits. We are now ready to expose the inner workings of the nucleus of the computer system — the processor.我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。
我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。
我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。
计算机专业英语2模拟试题2及答案
计算机专业英语模拟2Ⅰ. Vocabulary（词汇，30分）(一)．Translate the following words and expressions into Chinese.（写出下列词组的汉语，共10分，每题1分）1. central processing unit（CPU）中央处理器1. 2. operating system 操作系统2. 3. electronic spreadsheet 电子表格4. management information system 管理信息系统5. electronic commerce 电子商务6. database 数据库7. software engineering 软件工程8. software crisis 软件危机9. network security 网络安全10. computer virus 计算机病毒(二)．Fill in the blanks with the corresponding English abbreviations.（根据汉语写出相应的英语缩写，共10分，每题1分)1．随机存储器 RAM 2．局域网 LAN3．计算机辅助设计 CAD 4．数字视频光盘DVD5．通用串行总线 USB 6．面向对象编程 OOP 7．集成开发环境 IDE 8．结构化查询语言SQL9．多文档界面 MDI 10．企业之间的电子商务交易方式 B2B(三)．Match the following words and expressions in the left column with those similar in meaning in the right column.（将左列的词汇与右列相应的汉语匹配，共10分，每空1分）1. output b a.视频2. high-level language c b.输出.3. project window e c.高级语言4. black-box testing g d.应用软件5. multimedia h e.工程窗口6. WWW i f.系统软件7. field j g.黑盒测试8. application software d h.多媒体9. system software f i.万维网10.vidio a j.字段Ⅱ. Comprehension（阅读理解，40分）( )（一）Fill in the blanks with suitable words or expressions from the list given below, and change the form where necessary. （从下面方框中选择合适的词或表达，以其适当的形式填空，共10分, 每空2分)high-level language assembly language writtenmachine language notationA programming language, designed to facilitate the communication between human and computers, is a _ notation _ for describing computation in readable form. There are 3 levels of programming languages, they are_ machine language _ , which can be run directly by computer; ___ assembly language __ and _ high-level language _. There are different high-level programming languages. Fortunately, most of them have many kinds of construct in common and vary only in the way that these must be _ written __ . Therefore, first thing to be decided about a task is to choose which programming language is best suited for the job.Passage AThe central processing unit (CPU) is the heart of the computer systems. Among other things, its configuration determines whether a computer is fast or slow in relation to other computers. The CPU is the most complex computer system component, responsible for directing most of the computer system activities based on the instructions provided. As one computer generation has evolved to the next, the physical size of the CPU has often become smaller and smaller, while its speed and capacity have increased tremendously. Indeed, these changes have resulted in microcomputers that are small enough to fit on your desk or your lap.The CPU comprises the control unit and the arithmetic / logic unit (ALU). The control unit is responsible for directing and coordinating most of the computer systems activities. It determines the movement of electronic signals between main memory and the arithmetic/logic unit, as well as the control signals between the CPU and input/output devices.The ALU performs all the arithmetic and logical (comparison) functions —that is, it adds, subtracts, multiplies, divides, and does comparisons. These comparisons, which are basically “less than”, “greater than”, and “equal to”, can be combined into several common expressions, such as “greater than or equal to”. The objective of most instructions that use comparisons is to determine which instruction should be executed next.（二）Tell whether the following statements are true(T) or false(F) according to the passage A.（根据上文的内容判断下列句子的正误，共10分，每题2分）1. With the development of computer, the physical size of the CPU has often become bigger and bigger. ( F )2. The movement of electronic signals between main memory and the ALU as well as the control signal between the CPU and input /output devices are controlled by the control unit of the CPU. ( T )3. The CPU comprises the control unit and memory. ( F )4. The control unit performs all the arithmetic and logical (comparison) functions . ( F )5. The central processing unit (CPU) is the heart of the computer systems. ( T )Passage BA computer virus is a computer program that is created to make and spread copies of itself. The program may however also be designed to have other effects on the systems it infects, ranging from the annoying to the disastrous. Virus attacks are growing rapidly these days. According to BusinessWeek, the 76,404 attacks reported in the first half of 2003 nearly match previous year's total number . As new antivirus tools are more powerful than before, the virus writers are getting a lot smarter with newer and creative ways to attack network systems. Let's first examine some common virus types:Basic Virus - a piece of software code that is developed to attack computers and network systems via email or Internet connections. It quickly replicates itself and gradually attaches to files, programs or the hard drive.Trojan Horses - This is a program that doesn't replicate when entering a system but can be effectively used to open 'back doors.' Trojan Horses allow hackers to take control over a particular system or to steal very important data.Worm - this type of virus is able to spread itself automatically over the network from one computer to the next. During a worm attack, users' computers get infected without even having to click open email attachment or any program, etc.Since it is very difficult to avoid the virus, your best defense is a powerful antivirus program. In order to fight with such viruses, the software vendorsshould focus on making their products more robust. This may ask for a trade-off between user-friendliness and security. In specific cases it may require line-by-line inspection, code retooling and even systems automation to defend the installed programs.（三）choose the best answer according to the passage B.（根据上文的内容选择正确的答案，共10分，每题2分）1．A computer virus is a computer program that is created to make and spread C of itself.A．programs B．virus C． copies D．files2．Worm spread itself except by D .A．network B．E-mail C．program D．hardware 3．Antivirus program can scan and A virus.A．clean B．produce C．replicate D．make4．Trojan Horses C .A．quickly replicate itself and gradually attach to files, programs or the hard drive.B．infect the computer without even having to click open email attachment or any program.C．allow hackers to take control over a particular system or to steal very important data.D．avoid the virus to attack computer.5．According to Business Week, the B attacks reported in the first half of 2003 nearly match previous year's total number .A． 86,404 B． 76,404 C．56,354 D．34,876Passage CThe Internet, then known as ARPANET, was brought online in 1969, which initially connected four major computers at universities in the southwesternUS . The early Internet was used by computer experts , engineers, scientists, and librarians. There was nothing friendly about it. There were no home or office personal computers in those days, and anyone who used it, whether a computer professional or an engineer or scientist or librarian, had to learn to use a very complex system.The Internet matured in the 1970's as a result of the TCP/IP architecture. As the commands for E-mail, FTP , and telnet were standardized, it became a lot easier for non-technical people to learn to use the nets. It was not easy by today' s standards by any means, but it did open up use of the Internet to many more people in universities in particular. Other departments besides the libraries, computer, physics, and engineering departments found ways to make good use of the nets -- to communicate with colleagues around the world and to share files and resources.In 1991, the first really friendly interface to the Internet was developed at the University of Minnesota. The University wanted to develop a simple menu system to access files and information on campus through their local network.Since the Internet was initially funded by the government, it was originally limited to research, education, and government uses. Commercial uses were prohibited unless they directly served the goals of research and education. This policy continued until the early 1990's, when independent commercial networks began to grow.（四）Choose the best answer according to Passage C.（根据上文的内容选择正确的答案，共10分，每题2分）1. How many computers were connected to the initial Internet in 1969 ? BA. TenB. FourC. TwentyD. Three2. Only A could use the early Internet.A. computer experts, engineers, scientists, and librariansB. any experts, engineers, scientists, and librariansC. computer experts, engineers, scientists, and studentsD. experts, engineers, and scientists in universities in US3. The Internet became a lot easier for non-technical people to learn and use because of the common B .A. commandsB. protocolsC. topologiesD. architecture4. The first really friendly interface to the Internet appeared with theintroduction of a C system for files and information access.A. computerB. operatingC. menuD. application5. Which statement is not true according to Passage C? DA. Many more people in universities began to use the Internet in the 1970s, but it wasn't as user-friendly as today's standards.B. The restrictions to commercial uses changed as the independent commercial networks were not funded by the government.C. Commercial uses were allowed for the early Internet if they directly served the goals of research and education.D. The early Internet was logged in from home or office personal computers.Ⅲ.Translation（翻译，30分）(一) Translate the following sentences into Chinese.（将下列句子翻译成汉语，每题5分）1. SQL Server is designed to allow thousands of users to access the database at the same time and is a true client/server database system.1. SQL服务器用于允许成前上万的用户同时访问数据库，是一个真正的客户端/服务器端的数据库系统。
微软考试模拟试题NTWorkstation4试题二
微软考试模拟试题:NTWorkstation4试题二1. how do you print to a tcp/ip printer?a. host name and printer nameb. hostname and ip addressc. printer name and ip addressd. printer name and host nameans. c2. how do you trap packets of tcp/ip?a. network monitorb. snmpc. tcp/ipd. streams monitoringans: b2+. what protocol/service do you need to send tcp/ip trap messages to another computer?a snmpb simple tcp/ip servicesc nwlinkd network monitor agente dhcpanswer: a (may refer to 15 and 33 and 50)3. nt workstation is member of workgroup. you want to map network driver on your computer to a nt server in the corp domain. the guest accounts disable in the corp domain. ( 2 selection )a. logon to your ntws by using a user name from the corp domain.b. logon to ntws by the same user name you use to access to the nt server.c. select corp domain from logon dialog box.d. select connect as is the map network drive dialog box.ans: a,d3+. your computer is member of a workgroup. you want to map a network drive to a share on a server pdc in the xyz domain. the server has had the guest account disabled. choose two options.a log on to your workstation using your domain user accountb log on to your workstation using the account of a domain memberc in the log on box choose the domain named in the map network drive box in explorer choose 'log on using account' optione in the map network drive box in explorer choose 'connect as' optionanswer: a, e4. client service for netware :a. allow netware client to use share directory and printer on nt workstation.b. connect volumes or directory on netware.c. connect printer queues on netware.d. connect netware 4.1 volume on server that do not run bindery emulation.e. run netware 3.1 syscon utility from ntws.f. function as gateway to ntws for them ntws that do not have csnw installed.ans : b,c, e ,d pls refer 16. 5. nt workstation needs access nt server and netware server on network. what must you install on nt workstation ( select 2 )a. dlcb. tcp/ipc. netbueid. sap agent.e. csnw.f. nwlink ipx/spx compatable tranport.g. pptp.ans : e,f6. how do you start the backup program in a minimized window with low priority?a. start /min /low ntbackup.b. cmd /min /low ntbackup.c. net start /min /low ntbackupd. bat /min /low ntbackupans. a**7. several ms-dos share tsr program be loaded :a start it in its own ntvdmb start it in the default ntvdmc start it using config.ntd start it using autoexec.ntans: d8. you are planning to install nt workstation and 5 applications on 200 intel pc＇s. all pcs already have the same hardware and the same applications installed. you will install over the network with an nt server as the source of installation. which 3 files do you need:a. unattend.txt (answer file)b. setup.infc. sysdiff.exed. a udf filee. poleditans: a, c, d9. when you try to establish a ras connection with your department＇s server, the connectin is dropped after having been connected for a number of seconds. what is the best way to start investigating this problem?a. activate the device.log file, establish a connection and then view the contents of device. log.b. examine the connection error in the application log using event viewerc. examine the connection error in the system log using event viewerd. view the connection status using dial-up networking monitor.ans: d (a)10. you want to enable auditing for the hp printer attached to your windows nt workstation computer. which type of auditing events should you enable in user manager on your workstation?a. file and object accessb. use and user rightsc. user and group managementd. process trackingans: a【。
1996年全国计算机软件专业资格和水平考试系统分析员级试题及答案
1996年全国计算机软件专业资格和水平考试系统分析员级试题及答案试题1从供选择的答案中，选出应填入下面叙述中的_?_内的最确切的解答，把相应编号写在答卷的对应栏内。
评价软件的质量通常可以从产品运行、产品修改和产品转移等三个不同角度来进行。
除了软件应满足产品规格说明的正确性和保证运行效率以外，_A_和_B_也是产品运行期间影响软件质量的两个质量因素，其中_A_是指在遇到意外时系统能作出适应反应的程度。
可维护性是影响产品修改的一个质量因素，它主要包括可理解性、可修改性和_C_。
一般认为，_D_是影响产品转移的一个质量因素。
为了保证软件质量，在开发过程的各阶段进行_Ｅ_是一个重要的手段。
供选择的答案：A、B：①灵活性②可重用性③适应性④坚实性（健壮性）⑤可理解性⑥可用性Ｃ：①可测试性②可移植性③适应性．④坚实性（健壮性）Ｄ：①灵活性②可重用性③完整性④安全性Ｅ：①验收测试②用户培训③软件评审④文件修改试题2从供选择的答案中，选出应填入下面叙述中的_?_内的最确切的解答，把相应编号写在答卷的对应栏内。
面向对象程序设计的基本思想是通过建立和客观实际相对应的对象，并通过这些对象的组合来创建具体的应用。
对象是_Ａ_。
对象的三要素是指对象的_B_ 。
_C_均属于面向对象的程序设计语言。
而向对象的程序设计语言必须具备_D_特征。
Ｗｉｎｄｏｗｓ下的面向对象程序设计和通常ＤＯＳ下的结构化程序设计最大区别是_Ｅ_。
供选择的答案：A：①数据结构的封装体②数据以及在其上的操作的封装体③程序功能模块的封装本④一组有关事件的封装体Ｂ：①名字、字段和类型②名字、过程和函数③名字、文字和图形④名字、属性和方法Ｃ：①C++、LISP ②C++、Smalltalk ③PROLOG、ADA④FOXPRO、ADAＤ：①可视性、继承性、封装性②继承性、可重用性、封装性③继承性、多态性、封装性④可视性、可移植性、封装性Ｅ：①前者可以使用大量下拉式选单（ｍｅｎｕ），后者使用命令方式调用②前者是一种消息驱动式体系结构，后者是一种单向调用③前者具有强大的图形用户接口，后者无图形用户接口④前者可以突破内存管理６４０ＫＢ的限制，后者不能试题3从供选择的答案中，选出应填入下面叙述中的_?_内的最确切的解答，把相应编号写在答卷的对应栏内。
CENTUM CS3000简介
•输入/输出冗余 •远程IO
各种各样的现场设备上都可 以连接到相对应的通讯接口
CPU 冗余 -- Pair&Spare -
Vnet/IP
Coupler Coupler
两块CPU模块各 自独立工作，两 块CPU模块可以 进行无缝切换.
CPU module
CPU module
Vnet I/F
Main memory
FFCS
HF-Bus 1MBPS Dual Redundant Token Pass
EOPS
1975
CENTUM
COPS CFFS CFCS2CFCD2 CFCS EFCD
F-Bus 250 KBPS Dual Redundant Token Pass
CFCSCFCD
CENTUM CS 3000 R3
System alarm window
Node Interface Unit status window
远程HIS TS 系统结构
- 流程图操作
- 仪表面板操作 - 趋势画面 - 报警监视
HIS TS 可扩展到8个客户端
HIS
V net/IP
Office 局域 网 防火墙
Port:3389
FCS
Windows2003 TSE
HART
PROFIBUS-DPV1
主要部件
V net/IP (Control Network 控制网络) HIS (Human Interface Station 操作站) FCS (Field Control Station 现场控制站)
控制网络的发展
Vnet/IP 1 Gbps Vnet 10 Mbps HF-BUS 1 Mbps
operating system《操作系统》ch11-file system implementation-50
I/O Using a Unified Buffer Cache
11.32
11.7 Recovery
Consistency checking – compares data in directory structure with data blocks on disk, and tries to fix inconsistencies
Brings all pointers together into the index block. Logical view.
index table
11.20
Example of Indexed Allocation
11.21
Indexed Allocation (Cont.)
Need index table Random access Dynamic access without external fragmentation, but
Efficiency dependent on:
disk allocation and directory algorithms types of data kept in file’s directory entry
Performance
disk cache – separate section of main memory for frequently used blocks
File-allocation table (FAT) – disk-space allocation used by MS-DOS and OS/2.
11.17
Linked Allocation
11.18
File-Allocation Table
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TextSearchingonaHeterogeneousClusterofWorkstations
PanagiotisD.MichailidisandKonstantinosG.MargaritisParallelandDistributedProcessingLaboratoryDepartmentofAppliedInformatics,UniversityofMacedonia156Egnatiastr.,P.O.Box1591,54006,Thessaloniki,Greece{panosm,kmarg}@uom.grhttp://macedonia.uom.gr/∼{panosm,kmarg}
Abstract.Inthispaperweproposeahigh-performanceflexibletextsearchingimplementationonaheterogeneousclusterofworkstationsus-ingMPImessagepassinglibrary.Wetestthisparallelimplementationandpresentexperimentalresultsfordifferenttextsizesandnumberofworkstations.
1IntroductionTextsearchingisaveryimportantcomponentofmanyproblems,includingtextprocessing,informationretrieval,patternrecognitionandDNAsequencing.Es-peciallywiththeintroductionofsearchenginesdealingwithtremendousamountoftextualinformationpresentedontheWorldWideWeb(WWW)aswellastheresearchonDNAsequencing,thisproblemdeservesspecialattentionandanyimprovementstospeeduptheprocesswillbenefittheseimportantapplications.Thebasictextsearchingproblemcanbedefinedasfollows.Letagivenal-phabet(afinitesequencecharacters)Σ,ashortpatternstringP=P[1]P[2]...P[m]oflengthmandalargetextstringT=T[1]T[2]...T[n]oflengthn,whereboththepatternandthetextaresequencesofcharactersfromΣ,withm≤n.ThetextsearchingproblemconsistsoffindingoneormoregenerallyalltheexactoccurrencesofapatternPinatextT.Surveyandexperimentalresultsofwellknownalgorithmsforthistextsearchingproblemcanbefoundin[3],[9],[11],[16].Theimplementationofthetextsearchingproblemonaclusterofworksta-tionsorPCs[1]canprovidethecomputingpowerrequiredforthespeedupthesearchingonlargefreetextcollections.In[8],[12]fivesequentialtextsearch-ingalgorithmswereparallelisedandtestedonahomogeneousclustergivingverypositiveexperimentalresults.In[13]aperformancepredictionmodelwasproposedforstaticmaster-workermodelonahomogeneouscluster.In[10]aparalleltextsearchingimplementationwaspresentedforstaticmaster-workermodelandresultsarereportedfortheBrute-Forcetextsearchingalgorithm[11]onaheterogeneouscluster.Thecontributionofthisworkistheimplementationofaparallelflexibletextsearchingalgorithmusingclustercomputingtechnique.Thisalgorithmrealized
Y.CotronisandJ.Dongarra(Eds.):EuroPVM/MPI2001,LNCS2131,pp.378–385,2001.cSpringer-VerlagBerlinHeidelberg2001TextSearchingonaHeterogeneousClusterofWorkstations379themaster-workermodelwithstaticallocationoftexts.ItisimplementedinCinconjunctionwiththeMessagePassingInterface(MPI)library[6],[14],[15]whichfollowstheSPMD(SingleProgramMultipleData)modelandrunonaheterogeneousnetworkofworkstations.Theremainderofthispaperisorganizedasfollows:Section2brieflypresentsheterogeneouscomputingmodelandthemetrics.Section3discussesthetextpar-titioningstrategyandtheproposedparallelimplementation.Section4givestheexperimentalresultsoftheparallelimplementation.Finally,Section5containsourconclusionsandfutureresearchissues.
2HeterogeneousComputingModelAheterogeneousnetwork(HN)canbeabstractedasaconnectedgraphHN(M,C),where
–M={M1,M2,...,Mp}issetofheterogeneousworkstations(pisthenumberofworkstations).ThecomputationcapacityofeachworkstationisdeterminedbythepowerofitsCPU,I/Oandmemoryaccessspeed.–Cisstandardinterconnectionnetworkforworkstations,suchasFastEther-netoranATMnetwork,wherethecommunicationlinksbetweenanypairoftheworkstationshavethesamebandwidth.
Basedontheabovedefinition,ifanetworkconsistsofasetofidenticalwork-stations,thesystemishomogeneous.Further,aheterogeneousnetworkcanbedividedintotwoclasses:adedicatedsystemwhereeachworkstationisdedicatedtoexecutetasksofaparallelcomputation,andanon-dedicatedsystemwhereeachworkstationexecutesitsnormalroutines(alsocalledownerworkload),andonlytheidleCPUcyclesareusedtoexecuteparalleltasks.Inthispaperweuseadedicatedheterogeneousnetworkofworkstations.
2.1MetricsMetricshelptocompareandcharacterizeparallelcomputersystems.Metricscitedinthissectionaredefinedandpublishedinpreviouspaper[19].Theycanberoughlydividedintocharacterizationmetricsandperformancemetrics.
CharacterizationMetrics.Tocomputethepowerweightamongworkstationsanintuitivemetricisdefinedasfollows:
Wi(A)=min{T(A,Mj)}T(A,Mi)(1)
whereAisanapplicationandT(A,Mi)istheexecutiontimeforcomputingAonworkstationMi.Formula1indicatesthatthepowerweightofaworkstationreferstoitscomputingspeedrelativetothefastestworkstationinthenetwork.Thevalueofthepowerweightislessthanorequalto1.